Disomic Substitution of 3D Chromosome with Its Homoeologue 3E in Tetraploid Thinopyrum elongatum Enhances Wheat Seedlings Tolerance to Salt Stress

The halophytic wild relatives within Triticeae might provide valuable sources of salt tolerance for wheat breeding, and attempts to use these sources of tolerance have been made for improving salt tolerance in wheat by distant hybridization. A novel wheat substitution line of K17-1078-3 was developed using common wheat varieties of Chuannong16 (CN16), Zhengmai9023 (ZM9023), and partial amphidiploid Trititrigia8801 (8801) as parents, and identified as the 3E(3D) substitution line. The substitution line was compared with their parents for salt tolerance in hydroponic culture to assess their growth. The results showed that less Na(+) accumulation and lower Na(+)/K(+) ratio in both shoots and roots were achieved in K17-1078-3 under salinity compared to its wheat parents. The root growth and development of K17-1078-3 was less responsive to salinity. When exposed to high salt treatment, K17-1078-3 had a higher photosynthesis rate, more efficient water use efficiency, and greater antioxidant capacity and stronger osmotic adjustment ability than its wheat parents. In conclusion, a variety of physiological responses and root system adaptations were involved in enhancing salt tolerance in K17-1078-3, which indicated that chromosome 3E possessed the salt tolerance locus. It is possible to increase substantially the salt tolerance of wheat by the introduction of chromosome 3E into wheat genetic background.